As can be seen from FIG. 1, a reclosable bag 2 includes a reclosable zipper 4 that extends along the length of the reclosable bag 2 from a first side edge to the opposite side edge. The reclosable zipper 4 includes a first flange or closure member 6 and a second flange or closure member 8. First closure member 6 and second closure member 8 mate and unmate, seal and unseal, and otherwise close and open to provide access to the interior of bag 2. First closure member 6 includes a first profile 12 and second closure member 8 includes a second profile 14. First profile 12 is adapted to receive second profile 14.
Attached to the each of members 6, 8 is a polymeric panel or film 18 that forms the overall body of bag 2. Usually, members 6, 8 are extruded polymer. Each panel 18 is attached to its corresponding member 6, 8 by a sealant that has a lower melting point than either of members 6, 8, to inhibit members 6, 8 from melting when panels 18 are attached, which is typically done by the application of heat and pressure. In FIG. 1, polymeric panel 18 is attached to each of members 6, 8 by a sealant that is applied onto the exterior surface of each member 6, 8.
The process of manufacturing a reclosable bag containing a product typically involves three steps. First, a polymeric film is folded in half to form a first panel and a second panel. The first panel is attached to the first closure member and the second panel is attached to the second closure member. As described above, the panels or films are attached to the closure members by a sealant which is applied onto the exterior surface of each member. Heat, which melts the sealant between the closure member and the panel, is applied to fuse the polymeric panel its corresponding closure member. At this particular moment, the reclosable bag has a first edge and a second edge.
After the first and second members have been attached to their respective panel or film, the first and second ends of the reclosable bag are formed by fusing the first panel to the second panel. The panels are fused together by applying enough heat to melt the panels together thereby creating a seal between the first panel and the second panel. The heat that is used to form the first and second ends of the reclosable bag also seals the first and second ends of the first closure member to the ends of the second closure member, i.e. the first and second ends of the first closure member are fused to the first and second ends of the second closure member, respectively. This occurs because the heat that is applied to form the first and second ends of the reclosable bag is above the melting temperature of each closure member. Due to the rapid speed at which the first and second ends of the reclosable bag are formed, however, the first and second ends of the first closure member are occasionally not sealed to the corresponding ends of the second closure member. In other words, occasionally the first and second ends of the zipper are not completely sealed.
After the first and second ends of the reclosable bag have been created, the reclosable bag is filled with a product and usually sealed by locking the first closure member to the second closure member. The first and second closure members are locked together by mechanically engaging the first profile to the second profile. This is typically achieved by applying a force that pushes or crushes the profiles together.
After the reclosable bag has been formed, filled, and sealed, the bag is separated or “cut-off” from adjacent bags exposing the first and/or second ends of the zipper to the atmosphere. If the first and second ends of the zippers are not completely sealed, then the product that is contained within the reclosable bag may spoil as air is introduced into the interior of the reclosable bag by diffusing or otherwise flowing between the opposing interior surfaces of the first and second closure member. The seal is not hermetic.
In order to reduce the probability of having unsealed zipper ends, the rate at which the reclosable bags are produced is typically decreased. This increases the probability that sufficient heat is applied to both ends of the zipper for an adequate amount of time to seal the zipper's first closure member to the second closure member. One drawback to this method, however, is that the total number of reclosable bags produced over a given amount of time is reduced.
Therefore, there exists a need for a reclosable bag having a hermetic seal that can be produced at a high rate of speed.
This invention responds to this need by providing a zipper having a sealant applied onto the interior surfaces of the zipper thereby ensuring that a hermetic seal is formed when the reclosable bag is sealed.